EP0100600B1

EP0100600B1 - Portable tube milling tool

Info

Publication number: EP0100600B1
Application number: EP83303795A
Authority: EP
Inventors: Tollief O. Hillestad
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-07-29
Filing date: 1983-06-30
Publication date: 1988-06-01
Also published as: US4761104A; US4620823A; DE3376809D1; CA1210574A; EP0100600A2; EP0100600A3

Description

TECHNICAL FIELD

This invention relates to portable milling tools of the kind set forth in the classifying portion of claim 1.

BACKGROUND ART

Heretofore, milling tools have largely been of the standard or conventional or stationary type. That is, the milling machine was usually bolted or secured to the floor of a machine shop or factory and the work piece was brought to the machine for milling. With regard to work pieces which were brought from an outside location, use of the conventional stationary milling machines was costly, time consuming, and impractical. In order to alleviate this problem, hand grinders were utilised to grind the ends of the work piece to a desired shape. Not only was this method time consuming in that it required a few hours per item, but also expensive.
The present invention relates to a portable milling tool which can mill an item in approximately a few minutes, is of compact size, and can be used in the field or on the job site.
It is a problem in portable milling tools of the kind set forth to ensure that the shaft does not rotate otherwise there is the possibility of the tool itself moving bodily with consequent possible damage to the operator.
We are aware of WO-A-8201838 which discloses a portable milling tool of the kind set forth. However, in this construction, the shaft can rotate.
According to my invention a portable milling tool comprises a housing, said housing substantially enclosing an internal shaft guide, a pinion gear and drive gear, said housing further having a shaft extending through a portion thereof, one end of said shaft being tapered, said shaft having a remaining end portion, a collet means for securing a work piece, said collet means residing upon said tapered shaft, said remaining end of said shaft extending through another portion of said housing and having a feed nut means for causing said shaft to move forward or backward with respect to said housing and said shaft guide, said shaft guide having a bore therein, said pinion gear connected to said drive gear, means for mounting said drive gear for rotation within said housing coaxially with and axially spaced apart from said shaft guide, and a milling head, said drive gear connected to said milling head, characterised in that the said remaining shaft end is matingly received in the bore of the shaft guide for movement in an axial direction and is incapable of rotation in the bore of the shaft guide.
The co-operation between the shaft and the shaft guide ensures that the shaft cannot be rotated by the torque applied to the milling head and, in consequence, any danger to the operator is substantially eliminated.
Conveniently the portable milling tool has an in-line adjusting rod to engage or release a work piece, and an expandable collet is attached to one end of said adjusting rod.
The tool may be pneumatically driven and a pneumatic motor may be attached to said tool.
In one construction the said shaft axially moves the tool into or out of engagement with the work piece.
In use the tool can be fastened to an on-site tube, for example a boiler tube, and can mill the end of the boiler tube while located with a boiler.
These and other aspects of the present invention will become apparent from the following specification which describes in detail the present invention.

BRIEF DESCRIPTION OF DRAWINGS

For a brief understanding of the present invention, reference is made to the attached drawings herein which form a part of the specification and wherein:
Figure 1 is a partial cross-section elevational side view of an improved tool according to the present invention; and
Figure 2 is a cross-sectional view taken on line 2-2 of Figure 1.
The improved portable milling tool generally indicated in the drawings is very compact and yet efficient and can be utilized on the job site and actually on the tube, pipe, etc., without removing said tube, pipe, etc. from its surrounding environment.
The tool 110 has a housing 111. A shaft, generally indicated by the numeral 112, extends through housing 11 and extends from both ends thereof. One portion of the shaft is tapered at 131 for engagement with a collet. The taper can range from about 2 to about 15 degrees and preferably is about 5 degrees. Shaft 112 is hollow throughout, that is has a bore 132 which extends therethrough. A rod 135 extends throughout entire shaft bore 132 and as a knob or head portion 138. Generally such head portion is of convenient design such that it can be turned by a torque providing tool, as for example a wrench and the like. Rod 135 at its forward end has threads 139.
A collet residing on tapered shaft 131 is generally indicated by the number 140. Collet 140 has a pair of tapered jaws 142 which have serrations on the outside thereof to form a gripping surface. Since taper 131 is fully rounded, jaws 142 have an arcual internal surface. The taper of jaws 142 can be at any angle such as from about 2 to about 15 degrees and desirably is about 5 degrees. The jaws are attached to collet head portion 141 through any conventional fastening means such as screws and the like. Collet head 141 has internal threads 143 therein which matingly engage threads 139 of the rod. In order to maintain the jaws so that they are seated upon shaft taper 131, a resilient fastening means 145, such as an "0" ring is utilized. Collet 140 is moved either forward or backward, that is away from or towards housing 111, respectively, by turning knob 138 in one direction or another. Thus, through turning of knob 138, rod 135 is also turned. This causes collet 140 through engagement of rod threads 139 with colletthreads 143 to either ride up or down tapered shaft 131. Thus, when collet 140 is desired to be attached to the internal portion of a work piece, for example, a tube, pipe, etc., knobhead 138 is merely rotated in the proper direction causing the collet to ride up tapered shaft 136 and to expand the diameter of the serrated surfaces thereof. Upon being drawn backward a sufficient amount, jaws 142 wittengagethe internal surfaces of a work piece, not shown, automatically center it, and form a firm grip or securement therewith. Of course, any size shaft 131 and collet 140 can be utilized to engage and secure a correspondingly sized tube, pipe, etc.
As shown in Fig. 1, shaft 112 extends through the entire tool housing 111. The remaining or rear section of shaft 112 has threads 151 thereon. These threads extend along a sufficient portion of the shaft so that they extend into housing 111. Flange 152 resides on the housing and is connected thereto with any conventional fastener means such as screws. Flange 152 is integral with or connected to internal shaft guide 153. Hence, shaft guide 153 does not rotate. As best seen in Fig. 2, guide 153 has a hexagonal bore 154 which matingly engages the rear section of shaft 112 which is also hexagonal and has threads 151 thereon. Feed nut 155 has internal threads 156 which matingly engage said rear shaft hexagonal threads 151. Feed nutflange 157 also matingly engages bearing recess 158 of said internal shaft guide 153. Thus, through turning of feed nut 155, shaft 112 is forced either forwardly or rearwardly into or out of the housing. Due to the existence of ball bearings 159, feed nut 155 and flange 157 thereof are permitted to freely rotate within the housing when feed nut 155 is rotated. Shaft 112, however, does not rotate but moves axiallyforward or rearward through the hexagonal engagement with internal shaft guide 153, since contact of feed nut threads 156 with shaftthreads 151 forces the shaft either into or out of the rear portion of the tool. This provision of moving shaft 112 either forward or rearwardly provides contact or disengagement of the work piece with milling head 160. Should the work piece be stationary, rotation of feed nut 155 will cause tool 110 to be moved forward or backward. Feed nut 155 can be rotated by any conventional torque item such as a wrench to slowly draw the work piece or the tool into further contact with milling head 160.
A conventional pneumatically driven motor, not shown, can be attached to the bottom of housing 111. The pneumatic motor through pinion gear 129 engages drive gear 170. Bearings 176 permit drive gear 170 to freely rotate within housing 111. Similarly, bearings 177 permit the drive gear to freely rotate around the shaft. The drive gear is connected to milling head 160 as through keyways 161 or any conventional fastening device. Milling head 160 can be of any conventional design and have cutting edges 165 therein as made from tool type hardened steel.
The utilization of the portable milling tool is as follows. The tool with the forward portion of shaft 112 and collet 140 is inserted into a work piece such as a tube. Knobhead 138 is rotated to cause collet jaws 142 to move rearwardly or backward along shaft taper 131 and to expand into the inside of the tube. Rotation of knob 138 is continued until a tight and secured fit is obtained. Such operation automatically centers the tube and obtains a tight securement between collet 140 and the tube. An air motor, not shown, is then initiated. Pinion gear 129 drives main gear 170 which in turn causes milling head 160 to rotate. Feed nut 155 is then rotated to cause the work piece to engage milling cutting edges 165. Draw nut 155 is continued to be rotated until a sufficient degree and amount of milling of the tube has occurred. Naturally, cutting edges 165 may be at any desirable angle. Moreover, they can be of a specific configuration such as to form an offset on a particular work piece. Once a sufficient milling operation has been finished, feed nut 155 is rotated in the opposite direction, thereby withdrawing the work piece from it. Knob 138 is then rotated in a direction to cause collet 140 to move forward and thereby releasing tool 110 from the work piece.
According to the structure of the present invention, a very rapid milling operation is conducted upon a work piece such as a tube, a pipe, a conduit, and the like. The feature of the expandable collet ensures that the work piece ortool is automatically centered. Moreover, the provision of inline rod 135 as well as in-line shaft 112 permits a very small tool housing to be utilized. Accordingly, a very compact portable milling tool can be constructed according to the present invention. Thus, it can be utilized in numerous situations with regard to various in-the-field or on-job-site work pieces. A specific use involves the milling of boilertube ends actually located within a boiler. Due to the compact size of tool 110, it can be inserted within the tube end with collet 140 engaging the inside portion of the tube. As feed nut 155 is rotated, milling head 160 (and the entire tool) is caused to be moved towards the tube end. Such an operation saves immensurable costs in that the boiler tubes need not be removed and that the milling occurs actually within the boiler. After the operation is conducted, the tube ends can be welded together to obtain a secure and strong fitting. Moreover, due to the taper of milled tube, a much better weld is obtained.
Although the present invention finds particular use with regard to milling boiler tube ends, it is to be understood that it can be used in numerous types of operations whenever a work piece requires that an end thereof be milled. For example, the present tool permits header to be installed in boilers. Additionally, the tool can be used to remove various seal welds from various types of pipes, tubes, etc. The invention can also be utilized in the chemical industry, the petroleum industry, or wherever an on-site tube milling operation is desired.
While in accordance with the patent statutes, a best mode and a preferred embodiment has been described in detail, the scope of the invention is set forth by the scope of the attached claims.

Claims

1. A portable milling tool, comprising: a housing (111), said housing substantially enclosing an internal shaft guide (153), a pinion gear (129) and drive gear (170), said housing further having a shaft (112) extending through a portion thereof, one end (131) of said shaft being tapered, said shaft having a remaining end portion, a collet means (140; 138, 135) for securing a work piece, said collet means residing upon said tapered shaft, said remaining end of said shaft extending through another portion of said housing and having a feed nut means (155) for causing said shaft to move forward or backward with respect to said housing and said shaft guide, said shaft guide having a bore (154) therein, said pinion gear connected to said drive gear, means (177) for mounting said drive gear for rotation within said housing coaxially with and axially spaced apart from said shaft guide, and a milling head (160), said drive gear (170) connected to said milling head, characterised in that the said remaining shaft end is matingly received in the bore (154) of the shaft guide (153) for movement in an axial direction and is incapable of rotation in the bore of the shaft guide.

2. A portable milling tool according to Claim 1, characterised in that shaft feed nut means (138) matingly engages said remaining end portion of said shaft, and rotation of said shaft feed nut means (155) causes said shaft to move axially forward or backward.

3. A portable milling tool according to Claim 2, characterised by including a rod (139), said rod extending through said housing, said collet means attached to one end of said rod and having expandable jaws (142).

4. A portable milling tool according to Claim 3, characterised in that the rod (139) has a remaining end, and the remaining end of said rod has a-knob (138) thereon, whereby movement of said rod causes said collet jaws to move along said tapered shaft and expand or contract.

5. A portable milling tool according to Claims 3 or 4, characterised in that said shaft (112) has a bore (132), and said rod (139) extends through said shaft bore.

6. A portable tool according to any of Claims 3 to 5, characterised in that said collet jaws (142) are arcual and wherein said shaft taper is circular, and wherein said shaft taper is about 2 degrees to about 15 degrees.

7. A portable milling tool according to Claim 6, characterised in that a pneumatic motor is connected to said drive gear (170).

8. A portable milling tool, according to Claim 1 or Claim 7, characterised in that said guide bore (154) and said remaining shaft end are hexagonal.